How fast can you stack" Already part of P.E. classes in over 10,000 schools, Speed Stacks is a highly addictive, competitive game that combines speed, action, dexterity and coordination. Play solo against the clock or head-to-head against friends. Includes one button-cell battery. Set includes 12 competition-grade cups, StackMat to use as a smooth stacking surface, electronic timer, instructional DVD, and sport carrying bag.